Abstract 4924: Connective tissue growth factor (CTGF) mediates metastases of breast cancer stem cells.

Abstract

Abstract Background: Recent studies on various cancer types suggest that the mere acquisition of cancer stem-like cells (CSCs) phenotype is not sufficient to confer metastatic potential. Epithelial-Mesenchymal transition (EMT) has been implicated in enhancing cancer metastatic dissemination, and generating CSCs, which may be a key determinant in imparting metastatic potential to CSCs. Our goal is to determine the metastasis potential of the CSCs generated from EMT and to explore critical molecules involved in the metastatic cascade process. Experimental design and methods: The metastatic ability of the EMT-generated-CSCs (HMLE-Ras-Snail) and the control cell line (HMLE-Ras-vector) were compared by the migration, invasion and chemotaxis assays in vitro, as well as experimental and spontaneous metastases mice models in vivo. A microarray gene profiling analysis was performed to explore signaling molecules involved in the EMT-CSCs-metastasis. Functional assays were used to verify the identified molecule in vitro and in vivo. Results: HMLE-Ras-Snail cells showed significant high migration, invasive behaviors, especially under the different organ protein as chemo-attractants (lung, brain and liver). Experimental lung and brain metastasis mice study showed a significant enhancement of tumor extravasation and outgrowth of HMLE-Ras-Snail cells compared with the control cells. Spontaneous metastases mice studies showed that 7 out of 9 mice developed lung metastasis, and 2 out of 9 with brain metastasis for the HMLE-Ras-Snail model, while none of the HMLE-Ras-vector cell-injected mice were detected with metastases. Two-photon live animal imaging also showed enhanced single cell adhesion and movement in the lung or brain micro-vessels in the HMLE-Ras-Snail cell-injected mice. The differential gene expression analyses and western blot indicated that the CTGF is up-regulated in the EMT-generated-CSCs. Knockdown of CTGF in the HMLE-Ras-Snail cells not only enhanced the expression of epithelial marker and decreased the mesenchymal marker, but also decreased the in vitro proliferation, migration, invasion, mammosphere formation and in vivo lung metastases. Conclusions: CTGF may play an important role in breast cancer metastasis, with enhancing cell motility, invasiveness and also give cell self-renewal stem cell-like characteristic to facilitate EMT-CSCs-Metastasis. Citation Format: Jing Zhong, Xiaoping Zhu, Hong Zhao, Stephen Tc Wong, Stephen Tc Wong. Connective tissue growth factor (CTGF) mediates metastases of breast cancer stem cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 4924. doi:10.1158/1538-7445.AM2013-4924 Note: This abstract was not presented at the AACR Annual Meeting 2013 because the presenter was unable to attend.